In recent years, there have been many advances in electric motors driven by inverters with power from a direct current (DC) power source, such as a storage battery. In many systems it is desirable to provide small, high efficiency electric motor systems. Some examples include battery powered medical devices, small portable tools, hobbyist vehicles or aircraft, and miniature servo actuator systems. For instance, many military systems that operate on battery power are increasingly demanding smaller, higher efficiency electric servo controls because higher efficiency allows for longer operating times. Examples would include small unmanned aerial vehicles (UAVs), such as small drone aircraft or quadcopter aircraft, controls for small diameter missiles, and gun-launched projectiles.
Traditional motors include several multi-turn coils. Such motors have a relatively high back electromotive force (BEMF), and a relatively low motor constant. Moreover, as size decreases, such motor and their motor drive systems become increasing difficult to manufacture. In addition, as size decreases the efficiency of converting electrical power to mechanical power also inherently decreases.
It would be desirable to provide a high-performance motor system that includes a small motor that is also easy to manufacture. It would be desirable to provide a high-performance motor capable of operating in a battery powered system having low voltage batteries. It would also be desirable to provide such a motor that has low inductance and low resistance. Other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.